A new study that screened children in one South Korean city every year for more than a decade found that autism rates stayed flat across 12 consecutive birth cohorts. The researchers concluded that rising diagnosis numbers likely reflect better detection rather than more children developing autism.
The findings, published Sept. 14 in JAMA Pediatrics, arrive amid repeated claims from federal health leaders, including Health and Human Services Secretary Robert F. Kennedy Jr., that the United States faces an autism epidemic. For parents, the practical meaning is less about the national debate and more about whether a child who needs an evaluation gets one.
The key limitation comes first. The data come from a single city in South Korea, and the results may not apply directly to the United States, where diagnostic practices, school systems, and access to specialists differ.
Screening Every First Grader in One City for 12 Years
Researchers led by Dr. Young Shin Kim of Dell Medical School at the University of Texas at Austin screened incoming first graders in Goyang, a satellite city of Seoul, each year from 2005 to 2017, skipping 2011. The children were born between 1998 and 2010 and were about 7 years old when screened.
More than 62,000 children took part. Of those, 2,077 screened positive and were invited for full diagnostic testing, 881 completed assessments, and 447 received an autism diagnosis, according to CIDRAP's summary of the paper.
Across cohorts, the seven-year cumulative incidence of autism ranged from 1.9% to 3.2%, and prevalence at age 7 ranged from 2.0% to 3.4%. Neither measure showed a statistically significant rise or fall.
"This pattern suggests improved detection rather than increased ASD occurrence and does not support an ASD epidemic," the authors wrote, using the abbreviation for autism spectrum disorder.
This was an observational cohort study, not a trial. It found stable autism rates when the same active screening method was used year after year. It did not examine the causes of autism, and it cannot prove that no increase has occurred elsewhere. Current U.S. screening guidance has not changed.
One Korean City Cannot Settle the U.S. Question
The study's design is its main strength. Instead of counting children who happened to reach a doctor or a special education program, researchers actively screened entire classes using consistent methods, which removes much of the effect of changing awareness.
Its limits are just as real. Fewer than half of the children who screened positive completed diagnostic assessments, which can affect precision. Goyang is one city with its own health system and culture, and South Korean families may face different stigma and service pathways than American families.
The JAMA Network news release said interpretation of changing autism estimates "should account for methodological differences, changing service-use patterns, and ascertainment context in service-based surveillance systems."
That caution applies in both directions. The study weakens claims of an epidemic, but it does not rule out that some factors could shift autism risk in specific populations.
Wide Gaps Between U.S. Communities Reflect Detection
U.S. numbers show how much detection practices matter. The CDC estimates that about 1 in 31 children, or 3.2%, have been identified with autism by age 8, according to its latest surveillance data. That figure falls within the range the Korean study found.
Local rates vary sharply. In the CDC's monitoring report on 2022 data, prevalence among 8-year-olds ranged from 9.7 per 1,000 in Laredo, Texas, to 53.1 per 1,000 in part of California's San Diego area.
CDC researchers have pointed to differences in early screening programs, evaluation services, and access to care, rather than evidence that certain communities put children at greater risk. In other words, a child in Laredo is not known to be less likely to be autistic than a child in San Diego. That child may simply be less likely to be identified.
Parents Should Focus on Early Screening, Not the Epidemic Debate
The debate carries political weight. When the CDC released its 1-in-31 estimate in 2025, Kennedy described autism as an epidemic, while CDC researchers attributed much of the increase to improved identification.
For families, the most useful guidance is unchanged. The American Academy of Pediatrics recommends autism screening for all children at 18 and 24 months, and autism can sometimes be detected at 18 months or younger.
Parents who notice delayed speech, limited eye contact, loss of skills, or unusually repetitive behaviors can ask their pediatrician for a developmental screening and, when needed, a referral for evaluation.
Long waits for evaluations remain a real barrier in many communities. Families can ask about early intervention programs, which in many states serve children younger than 3 based on developmental delays without requiring a formal autism diagnosis first. MedicalDaily will follow new federal autism data and any response from HHS to the study.
Key Questions Answered
What did the study find? Autism incidence and prevalence stayed stable across 12 birth cohorts of children screened at about age 7 in Goyang, South Korea, from 2005 to 2017.
Does this prove there is no autism epidemic in the U.S.? No. It challenges epidemic claims, but the data come from one Korean city and may not apply directly to the United States.
Why have U.S. autism numbers risen? The CDC and many researchers attribute much of the increase to better awareness, broader screening, and improved access to evaluations.
How common is autism in the U.S.? The CDC estimates that about 1 in 31 children are identified with autism by age 8, with rates ranging from 9.7 to 53.1 per 1,000 across monitoring sites.
How reliable is the Korean study? Its consistent, population-wide screening is a major strength, but fewer than half of children who screened positive completed diagnostic testing, and it covered only one city.
When should children be screened? Pediatricians recommend autism screening at 18 and 24 months, with evaluation whenever parents or doctors have concerns.
What should parents do if they are worried? Ask a pediatrician for a developmental screening and referral, and ask about early intervention services while waiting for an evaluation.
